Abstract
Abstract:Radioactivity is associated with such mineral resources as rock phosphate, coal, rutile, and hematite. The concentrations of nuclides from the decay series of uranium, thorium and actinium in these mineral is at such level that may pose health risk for occupational exposure at mining and mineral processing industries, and public exposure to communities living around these areas. In South Africa, the protection of human health and the environment from the adverse effects of exposure to ionising radiation is regulated by both the NNRA (Act No. 47 of 1999) and the NEA (Act No. 46 of 1999) in line with the international dose limits for radiation protection. This study aimed at establishing the extent and distribution of the activity concentration levels of radionuclides in soil samples as well as various health parameters of ionising radiation across the study area. The motivation was to ascertain whether the exposure of workers and the nearby residents to ionising radiation due to anthropogenic activities within the Transnet port of Richards Bay was within the dose limit of 1 mSv.y−1 for public exposure and 20 mSv.y−1 for the occupationally exposed workers. For this study, representative soil, water, and fish samples were collected and analysed to assess the influence of rock phosphate storage on the environment including the aquatic habitat. A total of 90 soil samples, and 5 fish species were collected and analysed for 238U and 232Th using INAA techniques. Assuming a state of radioactive secular equilibrium, the samples were analysed for the activity concentrations of 226Ra and 40K using high energy gamma-ray spectrometry technique. ICP-MS was employed to measure the concentrations of heavy metals in 35 water samples...
Ph.D. (Physics)